DETERMINATION OF DISSOLVED-OXYGEN BY CATALYTIC REDUCTION ON A NAFION(R) RUTHENIUM-OXIDE PYROCHLORE CHEMICALLY-MODIFIED ELECTRODE

A Nafion(R)/ruthenium-oxide pyrochlore (Pb2Ru2-xPbxO7-y) chemically mo dified electrode (CME) was constructed for the determination of dissol ved oxygen (DO). Nafion(R), a perfluorosulfonated ion-exchange polymer , was first spin coated onto a glassy carbon electrode. Ruthenium oxid e pyrochlore particles were then synthesized in the Nafion(R) matrix b y treatment of Ru3+, Pb2+-exchanged polymer in alkaline aqueous soluti on with purging of O2 at 53-degrees-C for at least 1 day. The catalyti c reduction of DO on a Nafion(R)/ruthenium-oxide pyrochlore CME result s in fast and sensitive determination of DO in both acid and alkaline environments. The optimal conditions for the construction of such a CM E were thoroughly studied. The mechanism of detection is also discusse d. The analytical utility of the CME is demonstrated by application to underground water.